The present invention relates to an apparatus for high pressure pumping or homogenizing liquids, and comprises a drive motor with transmission mechanism which consists of a belt train, a gearbox and crank mechanism, as well as a pump section with pump block, valves and pistons connected to the above-mentioned crank mechanism, the crank mechanism being housed in a crankcase.
A high pressure pump substantially consists of a powerful electric motor, a transmission mechanism comprising belt train, gearbox and crank mechanism, as well as a pump section with pump block, valves and a number of plungers or pistons. The crank mechanism is housed in a crankcase. The rotary movement of the electric motor is converted by means of the transmission mechanism into the reciprocating movement of the pistons. The high pressure pump moreover includes peripheral equipment, such as operating devices, pressure gauge, lubricating system and electric system.
A common field of application for a high pressure pump is as a homogenizer. In those cases when the high pressure pump is employed as a homogenizer, the pump block is supplemented with one or more homogenizer devices or counterpressure devices wherein the homogenization process proper takes place.
Homogenization is an industrial process that has long been in use and whose purpose is to finely divide particles in different types of liquids, for example in order to stabilise emulsions, to accentuate flavour and aroma, to impart better colour saturation in paints, and so on. A very common field of application is milk homogenization, whose purpose is to shear the largest fat globules occurring in the milk into smaller fat globules and by such means stabilise the fat emulsion, which prevents cream setting. The major proportion of all consumer milk today is homogenized.
Homogenization normally takes place in that, for example, a fat emulsion which may consist of milk is given a high input pressure which drives the emulsion at high speed through a very narrow throttle or gap where the fat globules of the fat emulsion are broken up, among other things as a result of the turbulence which occurs on a sudden pressure drop downstream of the homogenizer valve. The product which is to be homogenized is pressurized, often up to several hundred bar, by means of the high pressure pump and is forced to pass through a narrow throttle or gap in the counterpressure device. Given that liquid foods such as milk are often treated in a homogenizer, it is essential that a high standard of hygiene be maintained.
Most homogenizers occurring on the market are of similar construction. The components included in the homogenizer are integrated on a common frame and are enclosed in a casing. Above all the electric motor which acts as a prime mover for the homogenizer or high pressure pump generates considerable heat during operation. The transmission mechanism and the pump section also contribute in heat generation. As a result of the construction of the homogenizer, it has hitherto proved difficult to realise an efficient air cooling of the mechanisms and components included in it. During a lengthy operational period, more and more heat is generated inside the casing of the machine, which may finally lead to failure, because of the fact that the load-supporting capability of the oil in the bearings is reduced considerably with increasing ambient temperature. Nor have prior art constructions hitherto afforded any possibility of leading off or making use of the surplus heat.
In those cases when the homogenizer is sound-proofed, all components are enclosed in a common insulated housing or casing which entails that the entire casing must be insulated in compliance with those standards which are required for hygienic machinery, i.e. machines which are employed for handling foods. Prior art designs of machine concept and casing have also resulted in the various parts in a homogenizer being difficult to access for service.
One object of the present invention is, by a specific design and construction of the apparatus for high pressure pumping or homogenizing, to obtain a controlled and governed air cooling of the components included in the apparatus.
A further object of the present invention is to lead off, or alternatively recover the surplus heat which the components of the apparatus generate.
Yet a further object of the present invention is that the construction of the apparatus divides up the high pressure pump or homogenizer into a hygienic section and a drive section, with the result that the drive section may be sound-proofed in compliance with considerably lower standards than those required for hygienic machines.
These and other objects have been attained according to the present invention in that the apparatus of the type described by way of introduction has been given the characterizing feature that the drive motor is placed above the crankcase and that the drive motor is surrounded on two sides by partitions which, together with an interconnecting roof, constitute an air channel.
Preferred embodiments of the present invention have further been given the characterizing features as set forth in the appended subclaims.